You can't tickle yourself.
29
The human brain doesn't stop developing until about 25 years old.
102
The average person's skin weighs twice as much as their brain.
131
Modern humans first appeared about 200,000 years ago, but record keeping didn't begin until about 6,000 years ago. That means about 97% of human history is lost.
21
The human eye blinks an average of 4,200,000 times a year.
233
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
We share 70% of our DNA with a slug.
218
The human brain is more active during sleep than during the day.
28